In recent years, treatment using a percutaneous surgical procedure with a catheter has been performed for treating the heart. The percutaneous surgical procedure with a catheter is minimally invasive, and therefore, is considered a desirable method if the technique can obtain the same effect as that of open heart surgery.
Examples of the treatment using the percutaneous surgical procedure with a catheter include treatment of atrial fibrillation, mitral valve repair, mitral valve replacement, left atrial appendage closure, and the like. In the atrial fibrillation, the atria enter a state of convulsion due to a state in which a disorderly electrical signal is frequently in the atria, and it has been known that abnormal automaticity occurring in a joint portion between the left atrium and the pulmonary vein is a primary cause of atrial fibrillation. For this reason, it has been known that it is effective to ablate (cauterize) abnormal automaticity by using an ablation catheter to reach the left atrium.
The mitral valve repair is performed in order to repair the mitral valve when there is damage or the like in the mitral valve, which is positioned between the left atrium and the left ventricle and suppresses the backflow of blood. In the mitral valve repair, the mitral valve is repaired through a catheter after the catheter reaches the left atrium. Similarly to the mitral valve repair, the mitral valve replacement is performed in order to replace the mitral valve with an artificial valve when there is damage or the like in the mitral valve. In the mitral valve replacement, the mitral valve is replaced with an artificial valve through a catheter after the catheter reaches the left atrium.
The left atrial appendage closure is performed in order to suppress the generation of thrombi by preventing the accumulation of blood in the left atrial appendage, and to thereby prevent an occurrence of cerebral infraction or the like due to the thrombi. In the left atrial appendage closure, the left atrial appendage is occluded by indwelling a wire or the like in the left atrial appendage through a catheter after the catheter reaches the left atrium.
In each of the above-described treatments, it is necessary to make a catheter reach the left atrium. As a method for this, a method, for example, a brockenbrough method or the like, has been known (for example, refer to U.S. Application Publication No. 2012/0179188) in which a hole is opened by piercing the atrial septum with a needle after making a catheter percutaneously reach the right atrium through the femoral vein or the like, and then, the catheter is made to reach the left atrium side through this hole.
However, when a hole is opened by puncturing the atrial septum as described above, there is a high risk of cyanosis or cardiac hypertrophy caused by blood flowing into the right atrium from the left atrium after treatment, depending on the size of the hole. Therefore, in some cases, treatment is required for occluding the hole in order to reduce the risk thereof. Particularly, in the mitral valve repair or mitral valve replacement, it is necessary to pass through a formed hole a catheter which has a comparatively larger diameter in order to accommodate a device for repairing the mitral valve, an artificial valve, or the like, therefore, the necessity to occlude the hole increases. As the method of occluding a hole, for example, a method has been known in which a hole is occluded using an occlusive instrument or the like which is indwelled in the hole by being enlarged in a disk shape on both sides of the left atrium and the right atrium. However, if such an occlusive instrument is attached to the hole, in a case where, for example, it is necessary to perform the same treatment again, there is a possibility that it may not be easy to perform the re-treatment due to the occlusive instrument inhibiting access of the catheter to the left atrium. In addition, such an occlusive instrument is a foreign material to a living body and easily forms thrombi.
In addition, when opening a hole in the atrial septum through the aforesaid puncturing, since the aorta is positioned in the vicinity of the septum primum, there is a possibility that the aorta may be punctured, which is the base of blood circulation to the entire body, due to the puncturing of the septum primum.